This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Giardiasis is the most frequent cause of non-bacterial diarrhea and currently there is no FDA approved medicine available. Class II Giardia Fructose-1, 6-diphosphate aldolase is one of the key enzymes associated with pathogenic microbe Giardia lamblia, the direct cause of giardiasis. The goal is to develop tight binding, reversible inhibitors of class II Giardia fructose-1, 6-diphosphate aldolase in Giardia lamblia for alternative treatments of giardiasis. By using molecular modeling technology involving Insight II and Autodock, several inhibitor candidates against Giardia aldolase have been designed. In the summer of 2006, major intermediates of one of the designed inhibitors, aminomethylphosphonosulfonamide (AMPS), have been synthesized.